1. Field of the Invention
The present invention relates in general to mobile communication devices, and in particular to the reduction of noise heard by a user of a mobile communication device.
2. Description of the Related Art
An important function of a mobile communication device is to adequately transmit human voice over a wireless network. One method to improve the transmission of voice using a mobile communication device is to filter the signal to reduce the background noise that is transmitted by the mobile communication device along with a user's voice. Some techniques for reducing background noise rely on known differences in the characteristics, such as the frequency spectrum, between human voice and typical background noise. Some techniques rely on measured differences between audio samples at different locations, such as nearer to and farther from the user's mouth. Noise suppression techniques are used alongside other methods, such as echo canceling, to improve the transmission of voice using a mobile communication device.
Noise filtering, as well as other signal processing tasks, such as signal encoding and decoding, are typically performed by one or more digital signal processors (DSPs) in the mobile communication device. A DSP can be implemented in various ways, such as an application-specific integrated circuit (ASIC), a portion of an ASIC, a programmable circuit, software code, or a combination including any of the above.